Electric clock



Dec. 16, 1941. J. FINK 2,266,015

ELECTRIC CLOCK Dec. N5, 194i.,

JL PMK Filed '29, was

5 Sheets-Sheet 5 Patented Dec. 16, 1941 ELECTRIC CLOCK Jean Fink, Waltham, Mass., assigner to Waltham Watch Company, Waltham, Mass., a corporation of Massachusetts Application November 29, 1939, Serial No. 306,658

7 Claims. (Cl. 'i4-126) This invention relates to electric clocks and the like of the type wherein an oscillatory time controlling element, such as a balance wheel or pendulum, is given periodic actuating impulses by electromagnetic means energized from a suitable source of electric current.

One object of the invention is to provide improved means for converting the. Voscillatory movements of the balance wheel or the like into rotary motion suitable for transmission to the dial train or equivalent time controlled mechanism, which means is capable of performing its intended function in an accurate and reliable manner with the consumption of a minimum amount of energy.

Another object of the invention is to provide an improved circuit closing device for controlling the circuit to the electromagnetic means, and consequently the timing of the impulses imparted thereby to the balance wheel or equivalent oscillating element, which device is operable by said element, likewise with the consumption of a minimum amount of energy, and in which the contacts are rendered automatically self cleaning as an incident to their operation.

The foregoing and other objects of the invention will best be understood from the following description of certain illustrative embodiments thereof shown in the accompanying drawings; these', however, having been chosen for purposes of exempliflcation merely, as it will be obvious to those skilled in the art that the invention, as defined by the claims hereunto appended, may be otherwise embodied without departure from its spirit and scope.

In said drawings:

Fig. 1 is a rear elevation, partly diagrammatic and partly broken away, of a clock mechanism embodying the invention.

Fig. 2i is a side elevation thereof.

Fig. 3 is an enlarged rear elevation of certain of the parts shown in Fig. 1.

Fig. 4 is a vertical section of the parts shown in Fig. 3.

Fig. 5 is a. view similar to Fig. 3 showing the parts in a different position.

Figs. 6 to 9 are diagrammatic views illustrating the operation of the mechanism for converting the oscillatory movement of the balance wheel into rotary movement of the dial train.

Fig. 10 is an enlarged detail section of the armature and pole pieces. L

Fig. 11 is a view similar to Fig. 3, showing a modification.

Figs. 12 to 15 are views similar to Figs. 6 to 9,`

but illustrating the operation of the mechanism shown inFig. 11. y

Referring particularly to Figs. 1 to 4, the frame of the clock mechanism comprises a pair of plates and 2i held in parallel spaced relation by bolts 22 and spacing sleeves 23, said frame providing or carrying the necessary supports, bearings, etc. for the various parts of the mechanism. Thev plate 2| carries at its outer side the conventional dial 24 over which move the usual hands 25 and 26 operated by a conventional type of dial gear train not shown in detail but two o1'- the gears of which are indicated at 2l and 28 in Figs. 1, 3 and 5.

Extending between the plates 20 andv2i, and journalled in suitable bearings therein, is an oscillatory balance staii' 29 to which is fixed a balance wheel 30 whose period of oscillation is controlled by a spiral or hair spring 3| secured at one end to the balance staff and at its opposite end to a stud 32 carried by the frame plate 20. The balance wheel 30 is composed of non-magnetic material, such as brass or copper, but carries at its periphery a short arcuate armature 33 of iron or equivalent magnetic material which, as the balance wheel oscillates, passes between the pole pieces 34 and 34' of the core 35 of an electro-magnet having an energizing coil 36 through which electric current from a suitable source 3l is periodically passed, under the control of circuit closing mechanism hereinafter described, to give periodic impulses to the balance wheel and thereby maintainA the latter in oscillation.

As herein shown, the core comprises a fiat iron or equivalent plate secured to the frame -plate 2i by bolts 38 and 38', while the pole pieces 34 and 34' comprise iiat plate-like arms extending toward one another in spaced parallel relation. The pole piece 34 comprises an integral extension of the core plate 35, being further held in position by one of the bolts 22 and the spacing sleeves 23 thereon, while the pole piece 34 comprises a separate member secured to the core 35 by the bolt 38 and connected magnetically therewith by an iron or equivalent bushing 39 onv said bolt. said pole piece being `likewise further held `in position by another ofthe bolts 22 and the spacing sleeves 23 thereon. The armature 33, as shown most clearly in Fig. 10, is oi' channel shape in cross section and is arranged to move between the pole pieces 34 and 34', being spaced from the latter by suitable air gaps 40.

'As shown in Fig. 1, one pole o! the battery 31 or other source of current is grounded, the

Aother being connected, throughV a conductor 4I,

with an insulated support 43 which in turn is connected by a conductor 44 with one terminal of the coil 36, the other terminal vof which is connected by a conductor 45 with the circuit closing device for controlling the periodic passage of current through said coil and the4 corresponding periodic impulses imparted to the balance wheel.

As shown in Figs. 1 to 5, the circuit closing means comprises a light and relatively short spring nnger 46 secured to an insulated support 41 (Figs. 1 and 2) to which thec conductor 45 is connected, and a similar but longer spring nger 48.1which is grounded as indicated in Fig. 1. The spring fingers 46 and 48 carry contact members 49 and 50, respectively, which, when said ngers are in the relative position normally maintained by their.` resilience, are separated, as shown in Fig. 5, but which are engaged with one another accomoconsumed when pin 52 moves inl a clockwise direction than during its movement in the opposite direction. Consequently, when the' supply of current to the device is interrupted,"

the current is again supplied the circuit through thecoil 36 will be closed and the mechanism when the nger 48 is flexed as shown in Figs. 1

and 3. The contactmembers'49 and 55 may be of any well known contact material, such' as platinum, iridium or silver.

Secured to the balance stai 2S isa collar 5l which carries a trip device in th form of a pin 52 disposed parallel tothe axis of said balance stai and spaced from the latter. The path of movement of the pin 52 intersects the end or tip of the longer spring finger 48, so that when, in the oscillation of the balance wheel, said pin moves in a clockwise direction as shown in Figs. l, 3 and 5 it engages and iiexes said nger in the direction of the ringer 46, forces the contact 50 against the contact 35, as shown in Figs. i and 3, and likewise slightly exes the finger 45, said pin thereafter passing the tip of the nger 3 which is restored by its resilience to its normal position as shown in Fig. 5. When the pin 52 in its movement in the opposite or counter-clockwise direction engages the tip of the iinger it it merely iieXes the latter idly in the direction away from the inger d5. Consequently the mechanism described acts to close lthe circuit through the coil 35 once in each complete oscillation period of the balance wheel and Sta. 1

The spring iingers t and l5 are of such light flexible construction that the operation above described consumes only a negligible amount oi the energy of thebalance wheel, so that the operation is not materially impeded. Also, the arrangement is such that when the nger 4S is flexed to force the contact 5@ carried thereby against the contact i9 carried by the ringer it and iiexes the latter, said contacts are given a slig'ht relative movement in a transverse direction, or longitudinally of the fingers, thereby rubbing upon one another so as to dislodge any foreign matter thereon and rendering said contacts self-cleaning. Separation of the contact members 39 and 55 breaks the circuit to the coil 3B quickly and normally induces a high voltage across said contact members, tending to cause sparking. To reduce any contact wear due to such sparking, a resistor element bushing 'i4 is preferably interposed between the supports 43 and 47, shunting the winding 35 electrically. This reduces said induced voltage and thereby "reduces sparking at the contacts.-

will automatically start. In order to provide for the unusual 'event that the parts should come to rest with the pin 52 in engagement with the opposite side o! the finger 48, thereby causing separation of the contacts 49 and 50, manual starting `means are preferably provided. Such means as shown comprise a spindle 53 journalled Vin the frame plate 20 and having at its outer end a manual operating knob 54. Secured to the spindle 53 are two arms 55 and 56, the former of which is normally held in engagement with one of the bolts 22, as shown in Fig. 1, by means of a spring 5l connecting the other 'of said arms with the frame plate'20. The spindle 53 carries a spring finger 58 which, when said spindle is y manually turned from the position shown in Fig. l and allowed lto' return, sweeps across the peripheryof the balance wheel, giving the latter a starting impulse.

As shown in Figs. l to 9, the mechanism for converting theA oscillatory movement of the balance wheel and stai'into rotary movement which is transmitted to the dial'train comprises a shaft 65 disposed with its axis transverse to the axis of the balance staii', journalled in brackets 6l secured to the frame plate 2i, and having fast thereon intermediate its ends a'worm 62 which meshes rwith teeth on the periphery of the gear 27. Secured to the 'end of the shaft i6 is a crown ratchet wheel'53 having an annular flange with ratchet teeth 5S cut in its edge. Secured to the hub of thebalance wheel 3G, and extending parallel to the axis of the latter at a short distance from the balance stad 29, is a light, at spring finger SS whose free 4end cooperates With the ratchet teeth 59, said free end being disposed with its atfaces at an inclination to its circular path of movement, as shown most clearly in Figs. 6 to 9. The spring finger 55 con-V l stitutes a driving pawl which cooperates with the ratchet for intermittently turning the driven shaft Gil in one direction as ythe balance Wheel and stai are oscillated. Figures 5 and 7 show that a side edge of the spring finger or pawl 55 drivingly engages a shoulder of a ratchet tooth. The inclination of the dat faces of the spring ringer 56 results in the transmission by said spring finger of a driving force which 'has a v 59. The angular end 'lli of the finger 59 acts as a holding pawl to hold the ratchet against retrograde movement and also cooperates with the driving pawl 63 in intermittently rotating the ratchet.

The operation ofthe spring ngers or pawls 66 and 69 in turning the ratchet 63 and driven shaft. 60 through a predetermined angular distance in one direction at each oscillation of the balance wheel and staii' is diagrammatically illustrated in Figs. 6 to 9. As th'e balance stafi' 29 turns in a clockwise direction, as shown in Fig. 6, the end of the finger 8B engages one of the ratchet teeth 59 and advances the latter into the position shown in Fig. 7, this movement being less in amount than one tooth space. During this movement the end 10 of the finger 69 rides up the inclinedr face of another oi' the ratchet teeth until it reaches the end of the latter as shown in Fig. "I, whereupon, due to the resilience oi' the finger B9, said angularend will drop behind the engaged tooth and, by a cam action on the edge of said tooth, as illustrated in Fig. 8, will complete the advance of the ratchet through one tooth space. carrying the tooth previously engaged by the finger 68 out of they path of the movement of thelatter which is thereby permitted to pass said tooth freely. Upon the return movement of the balance staff in'a counterclockwise direction, the inclined face oi' the finger 65 clears the previously engaged tooth engages the next tooth and is forced aside thereby, as shown in Fig. 9, so as to pass the same, the ratchet being at this time held against retrograde movement by the finger 89.

By reason of the co-a'ction of the spring nger 69 in completing the predetermined angular motion of the ratchet initiated by the finger 68, so as to permit the latter to pass freely out of engagement with the ratchet, both spring fingers can be made very light and flexible, and friction losses between the finger BB and the ratchet are minimized, so that the energy of the balance wheel and staff consumed in their operation isA very small. In order to hold the light, fiexible finger B6 up toits work and to steady and position the same during its ratchet advancing movement. while permitting it to readily yield when moving in the opposite direction, as shown in Fig. 9, there is preferably provided on the balance staf! 29 a fixed supporting collar 'i2 (Fig. 4) hav- Aing a slot 13 therein through which 'said finger passes, said slot being so disposed as to limit the flexure of the finger 88 in an outward direction while permitting free fiexure thereof in an inward direction.

A modification of the mechanism last described is illustrated in Figs. 11 to 15.. In this construction the ratchet 83', in addition to the ratchet teeth 59 cut in one edge, is formed at the opposite edge with teeth 'l5 having their adjacent faces oppositely inclined, the spacing of the teeth 'l5 being the same as that of the teeth 59. The spring finger 69 has a curved end 10 which coacts with the teeth to complete the angular movement initiated by the driving pawl or finger 68', as illustrated in Figs. 12 to 15. Thus, when the driving pawl 66 has, during the movement of the balance staff in a clockwise direction, ad-

.vanced the ratchet from the position shown in Fig. 12 to that shown in Fig. 13, the end 10' of the finger 69' will have been lifted to the end of the adjacent tooth 15 and thereafter, in riding down the rear inclined face of said tooth, as shown in Fig. 14, will, by cam action, complete the advance of the ratchet so as tocarry the ratchet tooth previously engaged by the finger 66 out of the path of movement of the latter, finally, as shown in Fig. 15, acting as a holding pawl to prevent retrograde movement of the ratchet when the finger 66 is snapped past the nextl ratchet tooth upon the opposite or vcounterclockwise movement of the balance staff.

In either constnuction described, th'e free end of the finger 8B' may be bent into the angular form shown in Figs. 12 to 15.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiments be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

1. In a clock or the like, an oscillatory driving member, a rotary driven member, and means for turning said driven member through a predetermined angular distance in one direction at each oscillation of said oscillatory member, said last named means comprising a crown ratchet wheel disposed with its axis transverse to the axis of said oscillatory member, a spring finger carried by said oscillatory member, extending parallel to the axis of the latter, having a face disposed at an inclination to its path of movement, and engageable with the teeth of said ratchet wheel during a portion of said movement, and a spring member fixed at one end and having a free angular 'end engageable with the teeth of said ratchet wheel.

2. In a drive mechanism, a rotary driver, a

driven member having teeth movable transversely of the axis of said driver, and an indexing leaf-spring mounted with one end on said driver and traversing said teeth, a side edge of said leaf-spring being drivingly engageable with a'shoulder of a tooth during a partial revolution of said driver, and the plane of said leaf-spring,

' at least in its tooth-contacting zone, being so inclined relative to said tooth shoulder as to provide a component tending to urge said spring towards the bottom of said shoulder.

3. In a clock or the likeya rotatable driver, a' toothed driven member, al fiexible indexing leaf-spring having one end anchored relative to `said driver. and presenting a side edge thereof for driving engagement with the teeth of said driven member, the plane of said leaf-spring in the vicinity of the tooth being so inclined to the engagement surface of the tooth as to provide a component tending to move said leaf-spring towards the bottom of said tooth, and stop means on said driver limiting movement of said leafspring towards the bottom of said tooth.

4. In "a clock or the like having an oscillatory `member, a toothed rotary Wheel, and means for holding saidwheel against retrograde movement, a driving pawl carried by said oscillatory member, said driving pawl comprising a leaf-spring of lesser thickness than width and having a far greater resilience in the direction of its thickness than in the direction of its width, said leafspring being arranged to drive the teeth of said wheel substantially in its direction of least resilience on its successive forward strokes and to be defiected by said teeth substantially in its direction of maximum resilience on its return strokes.

5. In a clockor the like having an oscillatory member, a toothed rotary wheel, and means for holding said wheel against retrograde movement, a driving pawl carried bysaid oscillatory member, said driving pawl comprising a leafspring of lesser thickness than width and having a far greater resilience in the direction of its thickness than in the direction of its width, said leaf-spring being arranged to drive the teeth. oi' said wheel substantially in its direction of least resilience on its successive forwardA strokes and to be deflected by said teeth subleaf-spring 'in its direction oi.' least resilience, and permitting exure thereof in its direction of maximum resilience. l

6. In a clock or the like, an oscillatory driving member, a driven member bearing projections, a driving element moving with said oscillatory member and arranged on its forward stroke to engage and drive one of the projections of said driven member thereby to move said driven member, and a second element arranged to cause movement of the aforesaid 'projection for a relatively substantial distance beyond the point to which it would have been brought by the rstmentioned driving element alone, thereby vto provide a relatively substantial clearance between said rst-mentioneddriving element and said proiection on the return stroke of the former, said second element also sewing to hold said. driven` member. against retrograde movement.

7. In a clock or the like, a rotatably-mounted toothed driven member, an oscillating driving element having a lpath of forward movement partially coinciding with the path of the teeth of said driven member and then relatively diverging therefrom, said driving element successively drivingly engaging the teeth of said driven member on successive forward strokes, and means acting on said driven member for successively bringing each engaged tooth forwardly a rela- 

